Operation

All slide switches must be switched to the right for normal operating mode. Connect a 9V DC power supply and the computer will begin running the program stored in ROM.

To program ROM, slide all switches to the left. Connect a microcontroller dev board (Arduino-like) per wiring guidance in the schematics. Code to perform the programming routine is available in my EEPROM Burner repository.

A small utility, hex.py, has been provided to generate the calls to the write function that are required (in EEPROM Burner) to transfer your binary to the ROM. Create a text file named hex.txt with hex codes, one byte per line, then run:

python hex.py

The included ROM image, 6502.asm, will capture keyboard input and display it on the LCD screen. This serves as a good template from which to build more complex applications.


Bill of Materials

# Part Type Properties
11 Ceramic Capacitor package 200 mil [THT, multilayer]; voltage 6.3V; capacitance 0.1µF
9 Electrolytic Capacitor package 100 mil [THT, electrolytic]; voltage 6.3V; capacitance 220µF
1 Electrolytic Capacitor package 100 mil [THT, electrolytic]; voltage 6.3V; capacitance 47µF
2 Electrolytic Capacitor package 100 mil [THT, electrolytic]; voltage 6.3V; capacitance 22µF
1 Ceramic Capacitor package 200 mil [THT, multilayer]; voltage 6.3V; capacitance 0.01µF
3 74HC08 Logic AND Gate variant Variant 1; pins 14; chip label 74HC08; editable pin labels false; package DIP (Dual Inline) [THT]; pin spacing 300mil; part # 74HC08
3 74HCT688E pins 20; hole size 1.0mm,0.508mm; chip label 74HCT688E; true; package DIP (Dual Inline) [THT]; pin spacing 300mil
1 74LS161A pins 16; hole size 1.0mm,0.508mm; chip label 74LS161A; true; package DIP (Dual Inline) [THT]; pin spacing 300mil
1 74LS244AN pins 20; hole size 1.0mm,0.508mm; chip label 74LS244AN; true; package DIP (Dual Inline) [THT]; pin spacing 300mil
1 WDC 65C02 pins 40; hole size 1.0mm,0.508mm; chip label WDC 65C02; true; package DIP (Dual Inline) [THT]; pin spacing 300mil
5 74HC04 pins 14; hole size 1.0mm,0.508mm; chip label 74HC04; true; package DIP (Dual Inline) [THT]; pin spacing 300mil
1 Voltage Regulator variant sink; chip 78005; package to220-igo; voltage 5V
1 28C256-15 EEPROM pins 28; hole size 1.0mm,0.508mm; chip label 28C256-15 EEPROM; true; package DIP (Dual Inline) [THT]; pin spacing 300mil
1 CY7C199-35PC SRAM pins 28; hole size 1.0mm,0.508mm; chip label CY7C199-35PC SRAM; true; package DIP (Dual Inline) [THT]; pin spacing 300mil
4 74LS32 pins 14; hole size 1.0mm,0.508mm; chip label 74LS32; true; package DIP (Dual Inline) [THT]; pin spacing 300mil
1 LCD screen pins 16; type Character
2 NPN-Transistor package TO92 [THT]; type NPN (EBC)
2 10kΩ Resistor tolerance ±5%; resistance 10kΩ; package 2512 [SMD]
2 5kΩ Resistor tolerance ±5%; resistance 5kΩ; package 2512 [SMD]
5 3.3kΩ Resistor tolerance ±5%; resistance 3.3kΩ; package 2512 [SMD]
1 Pushbutton package [THT]
5 74HC595 package DIP16 [THT]; type 74HC595
13 SWITCH_SPDT package kps-1290
1 POT variant 100k_3362u; package 3362u
1 mini DIN 6 Connector variant pth; package mini-din6; connector Mini-DIN6
1 Crystal frequency 1 MHz; package THT; type crystal; pin spacing 5.08mm